For moderate to high intensity exercise lasting 1.5-4 hours, Sports Dietitians Australia recommend a carb replacement rate of 1g carb /kg bodywt / hour. This is considered to be the body's maximum oxidation rate of carbohydrate, so 1g carb replaces the carb being burned. Note that fat is also being burned.

Taking more carb during exercise will result in it being converted to fat for storage, which is an unnecessary burden on metabolic pathways that should be providing energy to muscle.

Therefore, an 80kg athlete would consume a total of 80 grams of carb per hour. Most electrolyte drinks are a 6%-8% solution of carb, and if you drink a large bidon per hour say 750 mls, that's 750 mls * 0.06 = 45 grams of carb in the sports drink.

So you'd add 35 grams of maltodextrin per 750 ml bidon to get your 80g, which will provide 320 Cals per hour.

According to my Hi-5 Energy source carbohydrates can only be absorbed into the bloostream at a rate of 60g and hour unless you use the Energysource fructose mix which allows 90g an hour.

As far as I remember, provided glycogen stores are full, low to medium intensity excercise up to 1.5 hours should okay without energy drinks after that .5g per kg of body weight per hour. High intensity excercise, eg. racing, 1g per kg of body weight. Recovery is to be 2g per Kg of body weight per hour raced. For 1.5 hours after excercise the body can absorb twice as much carbohydrate into the bloodstream.

Bentnose wrote:According to my Hi-5 Energy source carbohydrates can only be absorbed into the bloostream at a rate of 60g and hour unless you use the Energysource fructose mix which allows 90g an hour.

As far as I remember, provided glycogen stores are full, low to medium intensity excercise up to 1.5 hours should okay without energy drinks after that .5g per kg of body weight per hour. High intensity excercise, eg. racing, 1g per kg of body weight. Recovery is to be 2g per Kg of body weight per hour raced. For 1.5 hours after excercise the body can absorb twice as much carbohydrate into the bloodstream.

â€¢ At low intensities (25-50% VO2 max), carbs during exercise reduce fat oxidation compared to fasted trainees.â€¢ At moderate intensities (63-68% VO2 max) carbs during exercise may reduce fat oxidation in untrained subjects, but do not reduce fat oxidation in trained subjects for at least the first 80-120 minutes of exercise.â€¢ Carbohydrate during exercise spares liver glycogen, which is among the most critical factors for anticatabolism during hypocaloric & other conditions of metabolic stress. This protective hepatic effect is absent in fasted cardio.â€¢ At the established intensity level of peak fat oxidation (~63% VO2 max), carbohydrate increases performance without any suppression of fat oxidation in trained subjects.

I can't find a reference off hand, but I recall reading that higher concentrations of carbs (greater than 8%) are harder to digest.

I use a mix of Gatorade powder and Maltodextrin. The recommended Gatorade dose is 3 scoops in 750ml, I use 2 scoops of Maltodextrin and 1 scoop of Gatorade for taste. I also throw a bit of salt and "no salt" (see here for the original - I've switched to adding Gatorade as it tastes far better ).

Cheers,Simon.

Phil Liggett, TdF 2011, Alpe-d'Huez: "I reckon tonight in hindsight he may have won the Tour de France tomorrow."

- Cottee's cordial, either sugared or not. Other cordials can be used. Just make sure the bottle (1 or 2 litre) makes up 10 litres of final drink. Most do.

Method:- pulverize the rennie tablets with mortar and pestle- if using sea salt, blend in a blender until finer- add the three powders to make up ~290 grams. - add extras like maltodextrin, BCAAs, alpha alanine, caffeine- mix well and store in freezer.- for each bottle of cordial concentrate (1 or 2 litre), add 29 grams of mixture (EDIT: PLUS 1/10th of the weight of the added extras)- when making up bottles for the bike, shake cordial bottle well, then add to water bottles as 1 part cordial mix to 9 parts water.

without amino acids and caffeine, cost is around $0.45 a litre.

Last edited by PawPaw on Tue Jan 17, 2012 5:34 am, edited 1 time in total.

notwal wrote:Fuel. It's starch - relatively low GI sugar. I put it in my biddens for rides over 50 km along with other stuff.

This is simply untrue. Maltodextrin has a GI of approximately 105, thus it has amongst the highest GI of any food.

BTW maltodextrin isn't starch either. Starch has very long chains and many branches. Maltodextrin has shortish (3 - 15 unit) chains with few or no branches (a 3 unit chain logically cannot be branched)

Death is usually triggered by caffeine's action on the nervous system. It causes ventricular fibrillation. Susceptible individuals with pre-existing or a family history of cardiovascular anomalies or morbidity may be adversely effected by a lower dose. It is not advisable to take caffeine in gels if you are sensitive to caffeine from any other source (coffee, tea, etc)

I don't think you really need a lot of caffeine. I note that Endura gels have only 8mg each. I don't use them often due to cost, but the impact is amazing. The 30mg in High5 gels doesn't do a whole lot extra, and I find I can't consume them continuously on a traingin ride, I have to mix them with 2 non-caffeinated to 1 or they start to get unpleasant and I stop taking them on.

8mg would have zero effect on anything... you must be very sensitive if you notice such a small amount. Haven't researched in a while as I know what works for me... but have seen quoted 4 to 10 mg per kilo of body weight... 10mg a kilo seems a lot to me but it obviously works for some... I stick to the lower end of the scale.

Perhaps I am ... it's like lighting the blue touch paper. In a minute or two I'm off, the fatigue vanishes and I feel no pain. Well, for awhile at at least. Then it's probably time for another gel.

A double-teaspoon shot of instant coffee at the start of the ride is a guaranteed 7% improvement over any set distance I can cover under an hour.

I had a bottle of V before the start of one particular 50km race. If it hadn't been for the dust making vision impossible, I'd have been able to stay on the back of the lead bunch for probably the first 10km instead of leading the train for the next lot.

Now if I could just stop doing stupid things to hurt myself that force me into time off the bike

I must admit I've never done more than a double shot of coffee within 10 minutes of race start. That's about 300 mg. If I weighed 77kg, that's almost 4mg/kg bodyweight. Two double shot mugs within 2 hours gets me twitchy.

Caffeine should be finished at least 1 hour before an event... Otherwise your going to want to pee ( or worse ) on the start line... I don't think it has as much affect if you drink a lot of coffee but if you abstain for a day or two before an event then there are definitely gains to be had.

TLL, I know a lot of studies have done the 3-9g/kg bwt 60 mins before start, but there's also been a number that recommend taking after your warm up, and continuing dosing during events, as often as every 15 minutes. I presume this is why Endura put 8mg in one gel.

Yes my drink mix has caffeine in it... But the big hit is taken in the time leading up to the event. My drink mix comes in 3 parts... The before part is finished at least an hour before the event... Then you drink the "during" in the hour before and during the event.